Hi,
I have no idea about the prizes for other places to compare, but I must say 10k reais (~5k USD) is a small amount of money for the value generate by this type of competition, in my opinion.
At the moment I am running through the organization I coordinate a challenge which will give prizes of this order, although we won't give it in cash, but a trip to Open Knowledge Festival http://2014.okfestival.org/ next July, books and games, all catalysing the creative use of technology and free software. And this is from a very tiny organization 6 month old.
The results from this competition led by the education program coordinator in Brazil seems good so far. I think one thing that could be improved was to consult the community in a more open way to avoid the actual wikidramas and I tend not to like prizes in cash, but simbolic one, like a trip to Wikimania would make much more sense for me or some prize related to photograph.
I don't criticize the organizers, they are newbies in the Wikimedia movement and let's assume good faith, but I think it's a good opportunity to discuss the issue globally, although the way the topic was raised.
Tom